static void Main(string[] args)
        {
            var certificateData = File.ReadAllBytes("YOUR_p7b_FILE");
            var cert            = new X509CertificateParser().ReadCertificate(certificateData);
            //I just wanted to know if I can see the publicKey somehow
            //var publicKey = cert.GetPublicKey();

            var store      = new Pkcs12Store(File.OpenRead("YOUR_p12_File"), "test".ToCharArray());
            var privateKey = store.GetKey("THE_NAME_OF_KEY_YOU_WANT_TO_GET").Key;

            var signedDataGen = new CmsSignedDataGenerator();

            signedDataGen.AddSigner(privateKey, cert, CmsSignedDataGenerator.EncryptionRsa, CmsSignedDataGenerator.DigestSha512);

            var zipContent = new CmsProcessableFile(new FileInfo("YOUR_DATA_FILE"));
            //For me a zip
            var signedData = signedDataGen.Generate(zipContent, true);

            var envDataGen = new CmsEnvelopedDataGenerator();

            envDataGen.AddKeyTransRecipient(cert);

            var sData     = new CmsProcessableByteArray(signedData.GetEncoded());
            var enveloped = envDataGen.Generate(sData, CmsEnvelopedDataGenerator.DesEde3Cbc);

            var dos          = new DerOutputStream(File.OpenWrite("YOUR_DATA_FILE.zip.encrypted.sig)"));
            var bytesToWrite = enveloped.GetEncoded();

            dos.Write(bytesToWrite, 0, bytesToWrite.Length);
            dos.Flush();
            dos.Close();
        }